Vacuum exhaust muffler



June 12, 19,45- c. R. HULL VACUUM EXHAUST MUFFLER Filed Nov. 2, 1945 2 Sheets-Sheet l www June 12, 1945. C. R. HULL VACUUM EXHAUST MUFFLER Filed NOV. 2, 1943 2 Sheets-Sheet 2 Ummm@ @ooo 0000 U00@ @moo cmo@ comb Patented June l2, 1945 UNITED STATES 1rATrNT OFFICE VACUUM EXHAUST MUFFLER Cecil R. Hull, West Palm Beach, Fla.

Application November 2, 1943, Serial No. 508,692

(Cl. ISL-51) 8 Claims.

The invention relates to exhaust mufflers particularly designed for airplane engines and has for its objects to provide new and useful imn provements in devices of this character.

One of the principal objects of the invention is to provide a muiller device wherein provision is made to eliminate the iiame ordinarily visible from the exhaust pipes of airplane engines, thereby rendering it more diilicult to determine the exact whereabouts of the airplane at night.

A further object of the invention is to pro vide a muffler of new and improved construction wherein provision is made to greatly decrease the volume of noise created by the engine or enl gines.

A still further object is to provide a muiller having a stream-lined construction, thereby promoting the flow of air and exhaust gases therethrough with a minimum of congestion or back ilow in the muffler. 4

A still further object is to provide a muffler device wherein the structure is such as to cre ate a partial vacuum on the exhaust side, theren by increasing the engine power by virtue of an increase in the engine R. P. M. This has the further advantage of causing the engine to run much cooler. In the instance of Diesel engines the instant improved muffler device eliminates slush in the motor exhaust.

The invention further contemplates the instant improved muffler device on automobile engines wherein it has the advantage of neutralizing or eliminating the danger of carbon monoxide in the engine exhaust, particularly in automobiles operating on low grade gasoline, so prevalent at the present time due to war conditions.

Numerous other objects and advantages of the invention will be apparent as it is better undei stood from the following description, which taken in connection with the accompanying` drawings, discloses a preferred embodiment thereof.

As a result of the instant improved muiiler conM struction wherein llame is eliminated, the hazard of planes burning in iiight or on the eld as a consequence of exhaust flame is greatly minimized if not completely removed. f

In said drawings:

Fig. l is a View in front elevation of the imm proved muffler device illustrated as connected on opposite sides to the outer ends of the exhaust collector ring of an airplane or other engine of the radial type. I v

Fig. 2 is an enlarged longitudinal horizontal section through the muiller per se, said View being taken substantially on line 2 2 of Fig. l.

Fig. 3 designates a, horizontal transverse sectional view taken substantially on line 3 3 of Fig. 2.

Fig. 4 is a similar view taken substantially on line 4-4 of Fig. 2.

Fig. 5 is a detail perspective view illustrating the rear or exhaust end of the mulller.

Fig. 6 is a view in side elevation of the improved muler illustrated as attached to the exv haust pipe or conduit of an airplane or other engine of the straight line type.

Referring to the drawings the improved mufiler device essentially comprises an inner tapered shell Ill and an outer tapered shell II spaced therefrom by means of a plurality of longitudinally extending circumferentially spaced and disposed spacer bars Illa, the latter being suitably secured as by welding or by other means to said inner and outer shells. This arrangement provides a plurality of spaced arcuate longitudinally extending chambers I2 between the said inner and outer shell elements. At the forward end of the muffler and secured thereto as by welding or other suitable means, is an enlarged hollow head I3, the latter having secured in open communication therewith by any suitable means, a pair of diametrically opposed tapered conduits or pipe connections I4, I4a. These latter mentioned conduits are reduced in area at their outer ends and are suitably secured respectively as by bolts or a welded connection, to the outer ends of the collector ring I5 (Fig. l). The extreme forward end of the muffler is in turn communicably connected as by welding, to the inner end of a cylindrical air flow pipe I6, the outer open end Il of which is freely exposed to the atmosphere.

A hollow plug I8 (Fig. 2) preferably of substantially partially truncated egg-shaped configuration, is illustrated as open but which may be closed at its rear end at Ilia, is disposed at the inner end of the air flow pipe I6 at the point of its juncture with the outer open end of the hollow muiller head I3, also of substantially parabolic or semi-globular configuration. Said plug is spaced inwardly from the inner walls of the pipe and head by means of a plurality of radially arranged spaced supports I9 extending inwardly from the inner end of the air flow pipe I6 formed integrally with the pipe or plug, or secured thereto and/or to the plug by welding or by means of any other suitable connection. The purpose of this construction is to provide and promote a Venturi effect on the air flow into the Said iins are illustrated herein as preferably four in number and are rigidly and communicably secured to the outer shell I I. Obviously the number and disposition of these hns may be varied if desired.

The interior of the muiller inwardly of the spaced shells I0 and II constitutes an open air and exhaust chamber 2I of gradually decreasing area or volume from the front to the rear or exhaust end thereof, said exhaust end of the chamber being indicated by the reference character 22. The outer wall 20a of each of the hollow ns 20 is preferably of straight configuration and has at its inner or forward end a dimension substantally equal to that of the diameter 0f the forward end of the outer shell II By virtue of this construction a lplurality of radially disposed tapered air and gas chambers 20h are provided within each hollow iin 2D. Communication between said inner chamber 2I and each chamber 20h dened by the hollow ns 20 is afforded by means of a plurality of longitudinally spaced transverse ports, apertures or conduits 23 extending between said inner and outer otherwise imperforate shell members I0 and I I, said ports being disposed in the longitudinally extending spacer bars or elements I2 in turn disposed between the inner and outer shell members I D and il.

A hollow tubular baille member 24 is mounted centrally of the hollow muiller head I3 by means of a pair of diametrically opposed supporting elements or webs 25 suitably secured as by welding to the inner wall of the head (Fig. 3). As illustrated said hollow baille element is preferably square in cross section and is disposed substantially in axial alignment with the inner open end Ia of the plug member I8. The side walls of the tubular baille element 24 are provided with a plurality of aligned and spaced apertures 26 to afford communication between the interior of the tubular baille member and the interior of the hollow parabolic head I3.

The forward end of the muiller inwardly of the hollow baille element 24 is preferably pro- 4 vided with a plurality of vertically disposed spaced baille plates 21 rigidly held in place within the inner shell member ID by means of an intermediate transversely or horizontally extending spacer and supporting plate 28 suitably secured as by spot welding to the shell III and to the baille plates. If desired forward and rear ring elements 29 may be provided to aid in maintaining the baille plates in spaced relation and to insure against longitudinal displacement thereof re1ative to the shell member I0. The said ring elements are also secured in place within the shell I0 in any approved mannerl preferably by spot welding.

A similar set or plurality of vertically disposed spaced baille plates 30 are mounted 'adjacent the rear end of the inner shell member I0 and are maintained in position by means of a horizontally disposed spacer plate 3i secured in any approved manner at its outer ends to the inner wall of the inner shell I0, and by front and rear wire ring members 32 similar in all respects to the ring elements 29. The horizontally disposed spacer plates or elements 28 and 3I are provided with spaced slits within which the baille plates 21 and 30 are inserted to maintain the latter in desirable uniformly spaced relation as best seen in Fig. 2 of the drawings. Each baffle plate 21 and 30 is provided with a plurality of spaced and aligned or staggered holes or apertures 33 thereby ailording communication between the spaced open ended chambers 34 deilned and set oil by the baille plate members 21 and 30.

The interior mufller chamber 2| between the described front and rear sets of rigidly mounted baille plates 21 and 30 is preferably provided with a plurality of horizontally disposed vertically spaced baille plates or elements 35 secured in any approved manner at their opposite ends to the inner w'all of the shell member I0. These baille plates 35 are similar to the plates 21 and 30 except in the plane of their right angular arrangement and are spaced between diametrically opposed inner shell walls lby means of a centrally disposed imperforate spacer plate member 36 suitably secured at its opposite ends to said shell walls and providedwith suitably spaced slots for receiving the various horizontally disposed vertically spaced baille plate members 35. Said baille members are also suitably perforated as indicated at 31 in staggered arrangement, to provide limited communication between the spaces 33 set off by the respective horizontally disposed plate elements 35.

In the operation of the device as is best seen in Figs. l and 2, the forward end ofthe muiller constitutes an air entrance pipe disposed between the inner adjacent ends of the collector ringarms I5 between the inner ends of the muiller conduits I4, I4a. The incoming air by-passes or moves inwardly circumferentially exteriorly oi the centrally disposed hollow plug IB with a Venturi eilect and enters substantially centrally of the hollow apertured tubular Ibaille member 24. This locality immediately inwardly of the hollow plug I8 and at the front and rear of the member 2l] of the incoming air mixes with exhaust gases from the engine cylinders entering the muiller tlrough the ports I4, I4a -from the collector ring A portion of these exhaust gases circulate through the enlarged hollow muffler head I3 and enter the tubular baffle member 24 through the perforations 26 in the side walls thereof. The combined air and gases thence enter between the spaced vertically disposed apertured plates 21 into the inner chamber 2I of gradually decreasing area and volume from front to rear thereof. From the forward end of said chamber the combined air and gases which are now of diminished pressure, enter between the intermediate horizontally spaced baille plates 35 into the intermediate portion of the chamber 2|. Thence said air and gases pass between the rearmost set of vertically disposed baille plates 30, similar in all respects to the forward set of such plates indicated at 21, The air and exhaust gases thereafter pass into the rear reduced portion 2| of the inner shell chamber and are discharged at materially decreased pressure through the open rear end 22 of the muiller.

During the described passage of the air and gases through the interior of the muiller from front to rear thereof, a portion of the same pass laterally through the radially disposed longitudinally spaced apertures or conduits 23 which are in spacer bars Illa, into the interior of the hollow longitudinally extending rearwardly flared or tapered radially disposed hollow nn 20 and are thence discharged into the atmosphere at the rear portion thereof as indicated at 20c in Fig. 2.

Fig. 6 shows the instant muffler arrangement when attached to the exhaust pipe of an in-line cylinder or Diesel motor.

From the above described manner of operation it will be obvious that the instant improved mufller is stream-lined to a great degree, the hollow fins 20 have a stabilizing effect on the muffler, thereby necessitating a minimum amount of bracing. The spaced communicating double shell structure I0, I I, 23 facilitates the air circulation between the shells as an incident to a materially increased cooling effect. The air and gases are materially reduced in pressure during theiry tortuous and baffled travel through the described longitudinally and transversely spaced parts of the mufer from the front to rear thereof as well as into the longitudinally disposed hollow fins which increase in volume and area as the same extend towards the rear exhaust end of the muffler. The three sections of perforated baffle plates alternately set at right angles to each other materially aid in breaking up and spreading of the force of the gases` Further a partial vacuum is promoted by the Venturi effect of the incoming air and exhaust gases mixing therewith from the conduits I4, Ma, at the locality of the hollow plug I8. The outward and rearward flaring of the laterally disposed hollow fins 20 causes and promotes additional suction on :the exhaust gases. Additional air enters the forward ends of the longitudinally extending chambers I2 between the inner and outer, shell members IU and Il, escaping at the rear ends thereof, for the purpose of promoting cooling of said shell members.

Briefly and generally summarized the described novel and structural features of the instant improved muffler device constitutes in effect an exhaust system wherein large volumes of air enter and pass through the annular Venturi channel adjacent the hollow plug II spaced from the inner walls of the air flow pipe I6. This causes a partial vacuum which pulls upon the entering exhaust gases from the inwardly and outwardly flared conduits I4, I4a. connected at their outer ends to the collector ring I5 of the airplane or other radial motor. After passing through the muffler the described air and exhaust gases are further sucked out by the outwardly flared ends of the hollow fins 20, as well as by means of the central opening 22 at the extreme rear and exhaustend of the device. This exhausting under materially reduced pressure has the desirable tendency to depart to the motor an increased R. P. M., causes the motor to operate at a cooler or reduced temperature, as well as more efficiently. The inner shell construction aids in cooling the exhaust gases quicker to a reduced temperature and hence reduces the volume of the gases in accordance with the recognized physical law and principles.

It is thought that the invention andmany of its attendant advantages will be understood from the foregoing description, and it will be apparent that various changes may be made in the form, construction and arrangement of the parts without departing from the spirit and scope of the invention or sacricing all of its material advantages, the form hereinbefore described being merely a preferred embodiment thereof.

What I claim is:

1. A muflier device comprising inner and outer continuous tapered shell members arranged in radially spaced relation throughout, a hollow fin element mounted on theouter of said shell members, said fin member being open at its rear end, a plurality of spaced baffle plates disposed within said inner shell member, means at the forward end of said muffler for admitting air thereinto, means disposed at the rear portion of said air admitting means for connecting said mufller with the exhaust conduit of an internal combustion engine, and a plug member disposed in spaced relation to the inner wall of said air admitting means for admitting air circumferentially therearound to the muffler interior so as to mix with the engine gases admitted to the muiller by said exhaust conduit.

2. A muffler device comprising inner and outer cylindrical continuous tapered shell members arranged in radially spaced relation throughout, a plurality of radially disposed hollow fin elements mounted on the outer of said shell members, said fin members being open at their rear ends and being of gradually increasing area from front to rear of the muflier, a plurality of spaced baflle plates disposed within said inner shell member, said baffle plates being perforated to provide communication between the spaces between said plates, means at the forward end of said muffler for admitting air thereinto, means disposed at the rear portion of said air admitting means for connecting said muffler with the exhaust conduit of an internal combustion engine, and a plug member disposed in spaced relation to the inner wall of the rear portion of said air admitting means for admitting air circumferentially therearound to the mufiler interior so as to mix with the engine gases admitted to the muffler by saidexhaust conduit.

3. A muffler device comprising inner and outer continuous cylindrical shell members arranged in equally radially spaced relation throughout and tapering inwardly from the front to the rear oi' the muffler, circumferentially disposed spacing means between said shell members, a plurality of radially disposed hollow fin elements mounted on the outer of said shell members, said fin members being open at their rear ends and being of gradually increasing area from front to rear of the mufller, a plurality of spaced sets of baffle plates disposed within said inner shell'member, said sets of baffle plates being perforated to provide communication between .the spaces between said plates, means at the forward end of said muffler for admitting air thereinto, means disposed at` the rear portion of said air admitting means for connecting said muffler with the exhaust conduit of an internal combustion engine, and a plug member disposed in spaced relation to the inner wall of the rear portion of said air admitting means for admitting air circumferentially therearound to the muffler interior so as to mix with the engine gases admitted to the muffler by said exhaust conduit.

4. A muffler device comprising inner and outer continuous cylindrical shell members tapering inwardly from the front to the rear of the muffler, said shell members being disposed in equal radially spaced relation throughout, circumferentially disposed spacing means between said shell members, a plurality of radially disposed hollow fin elements mounted on the outer of said shell members, said fin members being open at their rear ends and being of gradually increasing area from front to rear of the mufiler. a`plurality of sets of longitudinally spaced baille plates disposed within the inner of said shell members, said sets of baille plates being perforated and arranged at right angles to the contiguous set, the perforations in said baille plates providing for communication between the spaces between said plates, means at the forward end of said muilier for admitting air thereinto, means disposed at the rear portion of said air admitting means for connecting said muffler with the exhaust conduit of an internal combustion engine, and a plug member disposed in spaced relation to the inner wall of the rear portion of said air admitting means for admitting air circumferentially therearound to the muiller interior so as to mix with the engine gases admited to the muffler by said exhaust conduit.

5. A muffler device comprising inner and outer continuous cylindrical shell members tapering inwardly from the front to the rear of the muffier, said shell members being disposed in equal radially spaced relation throughout, circumferentially disposed spacing means between said shell members, a plurality of radially disposed hollow fin elements mounted on the outer of said shell members, said n members being open at their rear ends and being of gradually increasing area from front to rear of the muiller, a plurality of sets of longitudinally spaced baille plates disposed within the inner shell member,y said sets of baille plates being perforated and arranged at right angles to the contiguous set, the perforations in said baffle plates providing for communication between the spaces between said plates, means at the forward end of said mufller for admitting air thereinto, laterally extending means disposed at the rear portion of said air admitting means for connecting said muiller with the exhaust conduits of an internal combustion engine, and a partially spherical plug member disposed in spaced relation to the inner wall of the rear portion of said air admitting means for admitting air circumferentially therearound to the muffler interior so as to mix with the engine gases admited to the muiller by said exhaust conduit.

6. A muffler device com prising inner and outer continuous tape red shell members arranged in equal radially spaced relation throughout, a hollow fin element mounted on the outer of said shell members, said fin member being open at its rear end, a plurality of spaced baille plates disposed within said inner shell member, means eat the forward end of said muflier for admitting air thereinto, means disposed at the rear portion of said air admitting means for connecting said muiller with the exhaust conduit of an internal combustion engine, a plug member disposed in spaced relation to the inner wall of the rear portion of said air admitting means for admitting air circumferentially therearound to the muffler interior so as to mix with the engine gases admitted to the muiller by said exhaust conduit, and a hollow perforated tubular baille member spaced inwardly from and also disposed in spaced relation to and between said hollow plug member and the foremost set of said perforated baille plates.

'7. A muiller device comprising inner and outer continuousv cylindrical shell members tapering inwardly from the front to the rear of the mulfler, said shell members being disposed in equal radially spaced relation throughout, circumferentially disposed spacing means between said shell members, a plurality of radially disposed hollow fin elements mounted on the outer of said shell members, said iin members being open at their rear ends and being of gradually increasing area from front to rear of the muffler, a plurality of sets of longitudinally spaced baille plates disposed within the inner shell member, said sets of baffle plates being perforated and arranged at right angles to the contiguous set, the perforations in said baille plates providing for communication between the spaces between said plates, means at the forward end of said munler for admitting air thereinto, means disposed at the rear portion of said air admitting means for connecting said muiller with the exhaust conduits of an internal combustion engine, a plug member disposed in spaced relation to the inner wall of the rear portion of said air admitting means for admitting air circumferentially therearound to the muffler interior so as to mix with the engine gases admitted to the muffler by said exhaust conduits, and a hollow perforated tubular baille member spaced inwardly from and also disposed in spaced relation to and between said hollow plug member and the foremost set of said perforated baille plates.

8. A muffler device comprising inner and outer continuous cylindrical shell members tapering inwardly from the front to the rear of the muffier, said shell members being disposed in equal radially spaced relation throughout, circumferentially disposed spacing meansbetween said shell members, a plurality of radially disposed hollow fin elements mounted on the outer of said shell members, said fin members being open at their rear ends and being of gradually increasing area from front to rear of the muffler, a plurality of sets of longitudinally spaced baffle plates disposed within the inner shell member, said sets of baille plates being perforated and arranged at right angles to the contiguous set, the perforations in said baille plates providing for communication between the spaces between said plates, means at the forward end of said muffler for admitting air thereinto, laterally extending means disposed at the rear portion of said air admitting means for connecting said muiller with the exhaust conduits of an internal combustion engine, a hollow plug member of substantially spherical configuration disposed in spaced relation to the inner wall of the rear portion of said air admitting means for admitting air circumferentialy therearound to the mufller interior with a Venturi suction action so as to mix with the engine gases admitted to the muffler by said exhaust conduits, and a hollow perforated tubular baille member of substantially square cross section spaced inwardly from and also disposed in spaced relation to and between said hollow plug member and the foremost set of said perforated baille plates.

CECIL R. HULL. 

